The reactions of NO₂⁺ in association with heterogeneous water clusters

Abstract

Within the context of stratospheric chemistry the reactions of NO₂⁺ on ice particles represent an important loss mechanism for NO_x species via the formation and disproportionation of N₂O₅. Previous experiments involving NO₂⁺·(H₂O) _n clusters have identified reaction pathways leading to the formation of nitric acid and demonstrated that a small cluster can reproduce some of the essential features of chemistry on an ice surface (J. Chem. Soc., Faraday Trans., 1994, 90, 3469). In the new experiments reported here the fragmentation products of heterogeneous clusters of the form NO₂⁺·(H₂O) _n·X, for n in the range 1–10, have been examined for evidence of chemical reactivity, and in particular, for the effect X may have on nitric acid formation. X is one of the following: CH₃OH, C₂H₅OH, CH₃CN, NH₃ or CH₃COCH₃, each of which has been identified in the stratosphere in association with water molecules. Each molecule has a very individual effect on the chemistry of NO₂⁺, and to a large degree, patterns of behaviour appear to be influenced by relative proton affinities. However, the type of chemistry observed is very varied, ranging from the catalytic release of nitric acid which is promoted by the presence of acetone, through to the release of CH₃ONO₂, which results from the presence of methanol. Reactions of the type identified here could influence the chemical balance of the upper atmosphere and contribute to chemistry in polar stratospheric clouds.

References

1. P. J. Crutzen and F. Arnold, Nature (London), 1986, 324, 651.
2. M. R. S. McCoustra and A. B. Horn, Chem. Soc. Rev., 1994, 23, 195.
3. E. Arijs, Planet. Space Sci., 1992, 40, 255.
4. F. Arnold, in Proc. DAHLEM Workshop on Atmospheric Chemistry, ed. E. D. Goldberg, 1982, p. 273.
5. G. Hauck and F. Arnold, Nature (London), 1984, 311, 547.
6. E. E. Ferguson, F. C. Fehsenfeld and D. L. Albritton, Gas Phase Ion Chemistry, ed. M. T. Bowers, Academic Press, New York, 1979, vol. 1, p. 44.
7. A. J. Stace, J. F. Winkel and S. R. Atrill, J. Chem. Soc., Faraday Trans., 1994, 90, 3469.
8. J. F. Winkel, A. B. Jones, C. A. Woodward, D. A. Kirkwood and A. J. Stace, J. Chem. Phys., 1994, 101, 9436.
9. A. J. Stace and A. K. Shukla, J. Am. Chem. Soc., 1982, 104, 5314.
10. A. J. Stace and C. Moore, J. Am. Chem. Soc., 1983, 105, 1814.
11. A. J. Stace, J. Am. Chem. Soc., 1984, 106, 2306.
12. J. F. Winkel and A. J. Stace, Chem. Phys. Lett., 1994, 221, 431.
13. L. S. Sunderlin and R. R. Squires, Chem. Phys. Lett., 1993, 212, 307.
14. T. J. Lee and J. E. Rice, J. Am. Chem. Soc., 1992, 114, 8247.
15. F. Cacace, M. Attina, G. de Petris and M. J. Speranza, J. Am. Chem. Soc., 1990, 112, 1014.
16. S. G. Lias, J. F. Liebman and R. D. Levin, J. Phys. Chem. Ref. Data, 1984, 13, 695.
17. M. Aschi, F. Cacace, G. de Petris and F. Pepi, J. Phys. Chem., 1996, 100, 16 522.
18. P. Kebarle, S. K. Searles, A. Zolla, J. Scarborough and M. Arshadi, J. Am. Chem. Soc., 1967, 89, 6393.
19. Y. Cao, J.-H. Choi, B.-M. Hass, M. S. Johnson and M. Okumura, J. Phys. Chem., 1994, 98, 12 176.
20. Y. Cao, J.-H. Choi, B.-M. Hass, M. S. Johnson and M. Okumura, J. Chem. Phys., 1993, 99, 9307.
21. X. Zhang, E. L. Mereand and A. W. Castleman Jr., J. Phys. Chem., 1994, 98, 3554.
22. F. C. Fehsenfeld and E. E. Ferguson, J. Chem. Phys., 1973, 59, 6272.
23. F.-M. Tao, K. Higgins, W. Klemperer and D. D. Nelson, Geophys. Res. Lett., 1996, 23, 1797.
24. K. Leopold, M. Canagaratna and J. A. Phillips, Acc. Chem. Res., 1997, 30, 57.
25. A. Horn, T. Koch, M. A. Chesters, M. R. S. McCoustra and J. R. Sodeau, J. Phys. Chem., 1994, 98, 946.